This invention relates to valves having a reciprocable valve member connected to a stem for movement between open and closed positions, and more particularly to means for removably mounting the valve member on the end of the valve stem.
Heretofore, valves such as plug valves have included a reciprocable valve member mounted on the lower end of a valve stem and movable between open and closed positions relative to a fixed seat in the valve body. A valve member such as a tapered plug valve member has been attached to or mounted on the lower end of the stem by various means heretofore. Particularly for relatively large plug valves having flow passages over 3/8 inch in diameter, for example, the plug member has been attached to the stem for relative rotation with some amount of longitudinal movement between the stem and the plug member for achieving proper seating within the tapered valve seat. Some plug members, for example, have been attached to the stem heretofore with a snap ring and some have been secured by a threaded nut on the inner end of the stem.
The attachment for the plug valve member must be adequate to withstand the upward pulling force exerted by the stem in pulling the valve member to open position. Also, the tapered plug member should be mounted so that a simple and fast replacement may be provided such as may be necessary in the event of excessive wear or damage, and particularly without the use of any special replacement tools.